Surgical procedure. METS SMILES Total Knee Replacement

Transcription

1 Surgical procedure METS SMILES Total Knee Replacement

2

3 Surgical Procedure Contents Device information Product overview 1.2 Indications 1.3 Absolute contra-indications 1.4 Relative contra-indications 1.5 Capabilities and restrictions of use 1.6 Components of the SMILES Knee Trial components and instrument overview Components of the trial implants 2.2 SMILES Knee dimensions Femoral component Tibial component 2.3 Components of the trial implants 2.4 Special instruments 2.5 Jig tray 2.6 Femoral cutting guide Operation instructions and guidelines Pre-operative planning 3.2 Recommendations for component selection 3.3 General points to note when using trial components 3.4 Bone preparation 3.5 Tibial resection levels 3.6 Tibial preparation 3.7 Femoral cutting guide and bone preparation 3.8 Trial assembly and insertion 3.9 Implant assembly and insertion The femoral component Femoral plateau plates 3.10 The tibial component 3.11 Tibial plateau plates 3.12 Insertion of the axle and circlip 3.13 Use of circlip pliers Parts and order references 21 1

4 1.0 Device information 1.1 Product overview The SMILES knee system is designed as a modular system that can be used to replace diseased or deficient bone around the knee joint. The SMILES knee has three tibial options in two sizes; rotating hinge polyethylene tibia suitable for routine cases, rotating hinge metal cased tibia with short and long stems suitable for extra-articular resection or difficult revisions and a fixed hinge tibia with short and long stems suitable for knees with marked instability or gross deformity. For very special cases, the SMILES knee system can be used in conjunction with custom-made components to provide a rapid solution. For further details, please contact Stanmore Implants. 1.2 Indications Gross knee instability Unusual anatomy Failed primary knee replacements Complex revision arthroplasty 1.3 Absolute contra-indications Infection and sepsis 1.4 Relative contra-indications Inadequate or incomplete soft tissue coverage Uncooperative or unwilling patient or patient unable to follow instructions Foreign body sensitivity. Where materials sensitivity occurs, seek advice with respect to testing Obesity Vascular disorders, neuromuscular disorders or muscular dystrophy Inadequate tibial bone stock 1.5 Capabilities and restrictions of use The components are designed and manufactured and are to be assembled and used only in the manner specified. Any deviation from this may reduce the in-service life of the prosthesis. Mixing with unspecified components either from Stanmore Implants or from other manufacturers is not permitted since it may lead to mal-alignment, inadequate assembly, excessive wear and premature failure. A fully assembled SMILES knee replacement must consist of one femoral component (small or standard) pre assembled with bushes and one tibial component pre assembled with bumper pad, an axle and a circlip. The implant components are for SINGLE USE only and must not be re-used. A set of instruments is provided to assist prosthesis assembly, which includes a set of metal trial components. The trial components are anodised blue to easily distinguish them from implant components. In addition, the trial components cannot be used in conjunction with implant components. This implant is produced from titanium and CoCrMo alloys and therefore under no circumstances must it be allowed to come into contact with a stainless steel device as this would induce galvanic corrosion. 2 3

5 1.0 Device information 1.6 Components of the SMILES Knee Femoral plateau plates Optional titanium femoral plateau plates (not shown) are available in 5, 10, 15 and 20mm thicknesses for both small and standard sizes. Axle, bushes and circlip A cobalt-chromiummolybdenum axle, a pair of UHMWPE bushes and a titanium circlip. (Packaged with the femoral component). Femoral component Cobalt-chromiummolybdenum femoral component with a titanium stem. Anatomical for left and right sides. Available in small and standard sizes, with 140mm long femoral curved stem Ø13mm for standard components and Ø12mm for small components. SMILES Knee Knee components are available in small and standard sizes with three different types of tibial components. Bumper An UHMWPE bumper available in both sizes providing a secondary bearing surface and a soft hyperextension stop, preassembled within the tibial component. Rotating hinge metal cased tibia A UHMWPE tibial bearing with a Co-Cr-Mo tibial component and titanium casing. Stem lengths 140 or 180mm. Rotating hinge polyethylene tibia A Co-Cr-Mo tibial component with UHMWPE tibial bearing. Stem length 114mm for standard and 105mm for small knee. Fixed hinge tibia A Co-Cr-Mo tibial component. Stem lengths 140 and 180mm. Tibial plateau plates Optional titanium tibial plateau plates (not shown) are available in 5, 10, 15 and 20mm thickness for use with rotating hinge metal cased or fi xed hinge tibial components.

6 2.0 Trial components and instrument overview 2.1 Components of the trial implants Femoral plateau plates Trial femoral plateau plates (not shown) in 5, 10, 15 and 20mm thicknesses for both small and standard sizes. Trial femoral component Small and standard sizes in left and right versions. Trial axle One size axle that can fi t both small and standard components and can be inserted from either side of the knee. Trial tibial mono-blocks Represents each of the three tibial assemblies. Rotating hinge metal cased tibia Stem length 140 and 180mm in both standard and small sizes. Rotating hinge polyethylene tibia Stem length 114mm for standard and 105mm small size. Fixed hinge tibia Stem length 140 and 180mm in both standard and small sizes. Trial tibial plateau plates Plateau plates (not shown) in 5, 10, 15 and 20mm thickness for use with rotating hinge metal cased or fi xed hinge tibial components in both sizes. 4 5

7 2.0 Trial components and instrument overview 2.2 SMILES Knee dimensions Femoral component Small: 54mm Standard: 60mm Tibial component (Metal cased rotating hinge tibial component shown, dimensions are the same for all three tibial options) Tibial plateau Small: 62mm Standard: 68mm Small: 40.5mm Standard: 45mm Anterior

8 2.0 Trial components and instrument overview 2.3 Components of the trial implants Layer 1 1 Femoral plateau plate, small 20mm 2 Femoral plateau plate, small 15mm 3 Femoral plateau plate, small 10mm 4 Femoral plateau plate, small 5mm 5 Femoral plateau plate, standard 20mm 6 Femoral plateau plate, standard 15mm 7 Femoral plateau plate, standard 10mm 8 Femoral plateau plate, standard 5mm 9 Trial axle 10 Trial femoral knee, right/small 11 Trial femoral knee, left/small 12 Trial femoral knee, right/standard 13 Trial femoral knee, left/standard 14 Tibial plateau plate, small 20mm 15 Tibial plateau plate, small 15mm 16 Tibial plateau plate, small 10mm 17 Tibial plateau plate, small 5mm 18 Tibial plateau plate, standard 20mm 19 Tibial plateau plate, standard 15mm 20 Tibial plateau plate, standard 10mm 21 Tibial plateau plate, standard 5mm Layer 2 22 Tibial metal case, small/long 23 Tibial metal case, standard/long 24 Tibial metal case, small/short 25 Tibial metal case, standard/short 26 Tibial fixed hinge, small/long 27 Tibial fixed hinge, standard/long 28 Tibial fixed hinge, small/short 29 Tibial fixed hinge, standard/short 30 Tibial poly, small 31 Tibial poly, standard 6 7

9 2.0 Trial components and instrument overview 2.4 Special instruments Layer 1 1 Hammer (with soft ends) 2 Circlip pliers 3 General impactor 4 Pins (x2) 5 Tibial bearing impactor, standard 6 Positioning plate with holes, small 7 Positioning plate with slot, small 8 Positioning plate with holes, standard 9 Positioning plate with slot, standard 10 Tibial bearing impactor, small Layer 2 11 Tibial reamer metal casing, standard 12 Tibial reamer: Poly standard 13 Tibial reamer: Poly small 14 Tibial reamer metal casing, small 15 AR lug drill 16 Bush reamer, small 17 Bush compressor, standard 18 Tibial reamer: Fixed hinge 19 Bush compressor, small 20 Bush compressor nut 21 Bush reamer, standard 22 Osteotome

10 2.0 Trial components and instrument overview 2.5 Jig tray Layer 1 1 Femoral cutting block, standard 2 Femoral cutting block, small 3 Drill guide 4 Drill Ø8mm 5 Drill Ø10mm 6 Drill Ø2.5mm 7 Bone Pins x 7 8 Pliers 9 Distal cutting guide 10 Distal cutting guide bolt 11 Distal cutting guide slider 12 Distal cutting IM rod 13 Distal cutting guide plate 14 Tibial cutting guide rod 15 Tibial cutting guide prong 16 Tibial cutting guide rest In addition to these tools, the operating theatre should provide a bone saw, a set of flexible reamers and an appropriate cement application device. 8 9

11 2.0 Trial components and instrument overview 2.6 Femoral cutting guide In addition to these instruments, it is anticipated that the operating theatre should make available a bone saw, flexible reamers and an appropriate cement application device. Drill guide Ø10mm drill Distal cutting guide plate Ø8mm drill Distal cutting guide slider Distal cutting guide bolt Distal cutting IM rod Distal cutting guide Standard femoral cutting block Small femoral cutting block

12 3.0 Operation instructions and guidelines 3.1 Pre-operative planning It is important to assess the radiographs before the operation to establish approximate size of the components required for the patient. This will help reduce the number of trial components used during surgery. The following points should be considered during assessment: The size of the knee (Standard or Small) Choice of tibial component (Rotating hinge polyethylene, Rotating hinge metal cased or Fixed hinge) Length of tibial component (Short or Long. This only applies to rotating hinge metal cased and fixed hinge tibial components) Use of femoral and/or tibial plateau plates (for cases where there is extra articular resection) 3.2 Recommendations for component selection Size of femoral knee component Where possible, a standard sized knee component should be used if the bone and surrounding soft tissues can accommodate it. For smaller patients, a small sized femoral knee can be used. 3.3 General points to note when using trial components There is a single sized axle for the trial components, thus it can be used for both small and standard size knees. The axle can be inserted from either side. It should be noted that a circlip is not required for the trial components. The trial components are designed to give a representation of the volume of the actual implant component, and therefore, during trial reduction, they should provide an indication of the degree of soft tissue coverage and the function of the device. The trial tibial components represent only the size and shape of the actual tibial construct and therefore do not rotate. As the tibial canal preparation will vary according to the type of tibial component selected, it is advised that the correct trial tibial component is chosen, i.e. rotating hinge polyethylene, rotating hinge metal cased, or fixed hinge before any preparation of the tibia is undertaken. Tibial components Ideally, a rotating hinge polyethylene tibial component is recommended for cases where tibial cortical bone is strong as in most primaries and some revision cases. Rotating hinge metal cased tibial components are more suited for revision cases where the knee has reduced stability and/or where tibial plateau plates are required to maintain the joint line, for instance extra-articular resection. Fixed hinged components should be considered where there is marked instability of the joint. Plateau Plates For extra articular restrictions, femoral and tibial plateau plates can be used. Only one femoral and one tibial plateau plate can be used if required. The size of the plate corresponds to the size of the knee components (femoral component and tibial component), chosen

13 3.0 Operation instructions and guidelines 3.4 Bone preparation It should be noted that there is no prescribed order as to which bone (the femur or the tibia) is prepared first. Before femoral preparation, the size of the SMILES knee must be chosen as appropriate for the patient s knee. 3.5 Tibial resection levels Rotating hinge polyethylene Rotating hinge metal cased Fixed hinge Small 8mm Standard 8mm Small 11mm Standard 11mm Small 5mm Standard 5mm These dimensions are for guidance only. Due to degeneration and laxity of the knee, more bone may need to be trimmed if necessary.

14 3.0 Operation instructions and guidelines A B C Plate with slots for rotating hinge polyethylene tibia D 3.6 Tibial preparation Resect the tibial plateau using the tibial A cutting guide provided. Adjust the prongs of the tibial guide so that they sit into the condyles of the tibia. It is recommended that 8mm is resected for rotating hinge polyethylene tibial components, 11mm resection for rotating hinge metal cased tibias and 5mm resection for fixed hinge tibial components. (See figure 3.5). Based on the type of tibial component to B be used, place a tibial positioning plate onto the cut surface of the tibia ensuring the straight edge of the plate is on the posterior side. Also, since the straight edge of the plate corresponds to the axis of the knee joint, rotate it so that the foot is correctly orientated before fixing it using the pins provided. For a rotating hinge polyethylene tibial C component use the plate with slots. For rotating hinge metal cased and fixed D hinge tibias, use the plate with holes. Plate with holes for rotating hinge metal cased and fixed hinge tibial components

15 3.0 Operation instructions and guidelines E Ream the tibial canal through the E central hole using the appropriate reamer (specific for the type of tibial component chosen). For the rotating hinge metal cased and the fixed hinge tibial components, in addition to the proximal reamer (and if required), ream the distal canal to a depth of 140mm for short stems and 180mm for the long stems using a 12mm flexible reamer. For rotating hinge polyethylene tibial F component, use the osteotome to cut the slots to a depth of 8 to 10mm. F For rotating hinge metal cased and fixed G hinge tibial components, use Ø10mm drill piece to cut 10mm deep holes for the anti-rotational lugs. G

16 3.0 Operation instructions and guidelines A C 3.7 Femoral cutting guide and bone preparation Drill guide Patella rest Ø10mm drill Rotate the patella rest on the drill guide A until the correct size SMILES knee mark is aligned with the arrow on the top of the guide. Place the drill guide on the condyles of B the femur. B With the patella rest resting in the patella C track of the bone, rotate the drill guide in the sagittal plane and about the long axis of the bone so that the posterior condyles are aligned with the back edge of drill guide and that the patella rest is approximately in line with the femoral canal. Use the Ø2.5mm drill to prepare pin D holes, impact the bone pins to secure drill guide in place. Using the Ø10mm drill, drill through E the guide into the inter-condylar notch to the depth indicated by the stop located on the drill. Remove the guide. Using Ø8mm drill, deepen the hole ensuring the drill follows the intramedullary canal of the femur to the depth marked on the drill

17 3.0 Operation instructions and guidelines D Distal cutting guide IM rod E Guide slider Insert the IM rod into the distal cutting D guide for right or left femur making sure left/right mark aligned with arrow and lock it in position using the locking screw located in front of the distal cutting guide. The relevant marking should be proximal when inserting the rod into the guide. Locking screw Distal cutting guide slider bolt Assemble distal cutting guide, guide E slider, distal cutting guide slider bolt and the distal cutting plate. Using the chart below, adjust the guide slider for the amount of femoral resection measured from the femoral condyles and secure it by tightening the locking screw positioned above it. Size of SMILES Knee Slider reading Small 22mm Standard 24mm Distal cutting plate Note: These dimensions are for guidance only. Due to degeneration and laxity of the knee, more bone may need to be trimmed if necessary. Femoral cutting guide assembled correctly

18 3.0 Operation instructions and guidelines F Insert IM rod into the previously drilled F hole in the femur. Push the rod in as far as it can go, ensure that at least one of the femoral condyles is making contact with the distal cutting guide and then rotate the guide along the long axis of the femur to align the posterior condyles with the back edge of the cutting guide. Secure the cutting plate in place using the bone pins provided

19 3.0 Operation instructions and guidelines G Distal cut Unscrew the slider bolt and remove the G distal cutting guide, leaving the distal cutting plate securely in position. H Anterior cut Perform the distal cut using an oscillating saw within the slot on the distal cutting plate, and then remove the cutting plate. Place an appropriate size (small or H standard) femoral cutting block on the resected end of femur ensuring that the centralising peg is located in the previously drilled hole and that the sloping face is orientated posteriorly. Twist the block so that the sloping face is parallel with the posterior condyles. Secure the block into position using bone pins provided. Posterior cut Using the oscillating bone saw, trim the anterior condyles using the anterior surface of the block and posterior condyles using the posterior surface of the block. Remove the block using the pliers provided and using flexible reamers, ream the femoral canal to a depth of 140mm and to a diameter approximately 1mm bigger than the femoral stem. (Ø13mm for small size and Ø14mm for standard size). The femur is now prepared. Insert the chosen trial femoral component to establish cuts are correctly produced. If not, trim the bone as required.

20 3.0 Operation instructions and guidelines A 3.8 Trial assembly and insertion Select the required size and type of trial tibial mono-block and insert into the tibial canal. Select and insert the appropriate size femoral component. Join the two components together by inserting the trial axle ensuring that it is correctly seated before performing a trial reduction. Once satisfi ed, remove all trial components and select the corresponding implant components. 3.9 Implant assembly and insertion The femoral component Cement the required femoral component into the femoral canal, ensuring the correct orientation is achieved. Impact using the general impactor Femoral plateau plates Optional femoral plateau plates are available in 5, 10, 15 and 20mm thicknesses for both small and standard sizes. Using a small amount of bone cement, secure the plateau plate onto the femoral component by sliding it over the femoral stem until the anti-rotation lugs on the femoral component are located within the holes in the femoral plateau plate. It should be noted that only one femoral plateau plate can be used. Multiple plates cannot be stacked onto one another. If femoral plateau plates are required, they should be cemented onto the femoral component fi rst and then the femoral component should be inserted into the patient, as described in The tibial component Remove the inner tibial bearing component from the specifi c tibial casing chosen. For the rotating hinge arrangements, A cement the appropriate tibial component into the tibial canal, i.e. for rotating hinge polyethylene assembly, cement the long plastic tibial component and for the rotating hinged metal cased tibial arrangement, cement the outer metal tibial casing. Impact using the appropriate impactor. For rotating hinge polyethylene, impact using the plastic impactor; and for the rotating hinged metal cased, impact using the general impactor. Once cemented securely in place, insert the tibial bearing components into the cemented tibia. For the fi xed hinge tibial arrangement, cement the component into the canal and impact using the general impactor

21 3.0 Operation instructions and guidelines A B 3.11 Tibial plateau plates Optional tibial plateau plates are available in 5, and 20mm thickness for use with the rotating hinge metal cased or fi xed hinge tibial components. Using a small amount of bone cement, secure the plateau plate onto the tibial component by sliding it over the tibial stem until the anti-rotation lugs on the tibial component are located within the holes in the tibial plateau plate. The tibial component can then be inserted as described in section It should be noted that only one tibial plateau plate can be used, multiple plates cannot be stacked onto one another. If a larger tibial block is required for extra articular resections, a custom component can be manufactured on request. Please contact Stanmore Implants for further information Insertion of the axle and circlip Align the femoral and tibial components A and insert the axle into position as shown. It should be noted that the axle can be inserted from either side of the knee joint. Using the pronged end of the circlip B pliers handle, push the axle in place. If required, rotate the axle to engage the axle head into the offset recess in the femoral component. Check to ensure the axle head is correctly seated inside the recess and that it is not trapped within the circlip groove. Secure the axle by inserting the circlip, so that is is seated inside the circlip groove as described in section 3.13.

22 3.0 Operation instructions and guidelines A B Correct D E 3.13 Use of circlip pliers Locate the circlip onto the circlip pliers. The circlip and the pliers are designed A to clip together for ease of use. The best way to place the circlip onto the pliers is by holding the circlip on your finger tip and then pushing the pliers into it ensuring the central pin locates in the centre of the circlip and the two moving jaws are either side of the central strips of the circlip as shown in the pictures below. A correctly inserted circlip is shown B with the jaws of the circlip pliers in the correct position. This picture shows an incorrectly C inserted circlip. This will not function and the circlip requires reinserting. (Rotating 180 ). The circlip is best inserted into the knee D by holding the circlip at an angle, then placing the circular part of the circlip into the circlip groove in the tibial component and then straightening and pushing the circlip into position as shown. Release circlip pliers and pull to unclip from the circlip. Ensure that the circlip is seated inside E the circlip groove in the tibial component and then using a pointed implement, rotate the circlip to ensure it turns inside the groove. Rotation of the circlip ensures the circlip is fully engaged in the circlip groove. C Incorrect 20 21

23 4.0 Parts and order references Femoral knee Components Small Left mptfc/lsm Small Right mptfc/rsm Standard Left mptfc/lstd Standard Right mptfc/rstd Tibial: rotating hinges Small mkrhp/sm Polyethylene Standard mkrhp/std Tibial: rotating hinges Small Short Stem mkrhm/smst Metal cased Standard Short Stem mkrhm/stdst Small Long Stem mkrhm/smlg Standard Long Stem mkrhm/stdlg Tibial: fixed hinges Small Short Stem mkfh/smst Standard Short Stem mkfh/stdst Small Long Stem mkfh/smlg Standard Long Stem mkfh/stdlg Femoral: plateau plates Small 5mm mkfp/sm5 Small 10mm mkfp/sm10 Small 15mm mkfp/sm15 Small 20mm mkfp/sm20 Standard 5mm mkfp/std5 Standard 10mm mkfp/std10 Standard 15mm mkfp/std15 Standard 20mm mkfp/std20 Tibial: plateau plates Small 5mm mktp/sm5 Small 10mm mktp/sm10 Small 15mm mktp/sm15 Small 20mm mktp/sm20 Standard 5mm mktp/std5 Standard 10mm mktp/std10 Standard 15mm mktp/std15 Standard 20mm mktp/std20

24 Notes 22 23

25 Notes

26 Notes 24

27 QL054/1/NOV Stanmore Implants Worldwide Ltd. No reproduction, even partial is permitted without prior written authorisation from Stanmore Implants Worldwide Ltd.

28 Stanmore Implants 210 Centennial Avenue Centennial Park Elstree WD6 3SJ United Kingdom T +44 (0) F +44 (0)